1. Field of the Invention
The invention relates generally to the field of computer software and, more specifically, to estimating light color and direction for augmented reality applications.
2. Description of the Related Art
An augmented reality application is a type of computer software application that is used to digitally enhance real-world video images of a real-world scene captured through a video camera. One aspect of digitally enhancing the video images is inserting computer-generated graphics objects into the video images. By recognizing fiducial markers manually placed in the real-world scene captured by the video images, the augmented reality application determines the location in the video images where the computer-generated graphics objects should be inserted. The video images are then augmented by inserting the computer-generated graphics objects in the video images.
When inserting computer-generated graphics objects into the video images, it is important to shade and adjust the lighting of the computer-generated graphics object based on the lighting conditions in the real-world scene. Traditionally, the shading and the lighting of a computer-generated graphics object is pre-determined before the video image is digitally enhanced. Such a technique requires specialized hardware configured to collect lighting values from the real-world scene before the video image is captured. The lighting values are then processed to determine the lighting conditions in the real-world scene. The augmented reality application then generates the computer-generated graphics object such that the computer-generated graphics object is shaded according to the determined lighting conditions. Once generated, the computer-generated graphics object is inserted into the video images.
One drawback to this technique is that the augmented reality application must process each video image twice, once to determine the lighting conditions and again to digitally enhance the video image. Such an approach is thus computationally inefficient. Another drawback is that the specialized hardware used to determine the lighting conditions can be expensive and difficult to obtain.
As the foregoing illustrates, what is needed in the art is an effective technique for determining lighting conditions in a real-world scene for augmented reality applications.